The present invention relates to a method and a device for compacting feedstuff or the like in a tube to be placed on the ground as the mobile device is propelled.
The device includes a traction vehicle, a trailer unit connected to the traction vehicle, a container for the feedstuff, and a rotatable feeding screw mounted at the rear of the trailer unit for feeding the feedstuff from the container into the tube where it is compacted. The device has a brake system for braking the wheels of the trailer unit to produce a braking force while the feedstuff is being fed into the tube.
U.S. Pat. No. 4,949,633 discloses such a mobile device, which may serve as an example of the relevant background art.
The extraction of sugar from sugar beets gives a by-product in the form of beet pulp, which can be used as stock feed. As a result of the severe cleanliness regulations that apply to the transportation of beet pulp from the sugar works to the animal breeders, as well as to the actual storage at the breeders', high demands are placed on the transport vehicles, the handling equipment and the storage tanks. The beet pulp must not come into contact with any impurities, such as earth, which would easily render it unfit as stock feed. If stored for a long time at the breeders', the beet pulp must not come into any contact with air.
With this in mind, a method has recently been developed in which a strand of beet pulp is compacted in an elongate plastic tube which is placed on the ground somewhere near the stables of the breeder. The tube, which may be up to about 70 m long and have a diameter of about 2.5 m, is closed at one end and can be opened at the other end where the pulp can be removed when required. Naturally, this end is carefully closed after each withdrawal of pulp, and the pulp in the tube is thus kept hermetically sealed off.
Such strands of compacted beet pulp in plastic tubes have hitherto been placed on the ground by means of a vehicle assembly made up of a conventional tractor and, connected thereto, a trailer carrying a container for the pulp. At the bottom of the container, there is provided a feeding screw connected to the power-take off of the tractor and adapted to feed the pulp out of the container and into the tube which is fastened on a special supporting collar at the rear of the trailer.
In operation, the beet pulp is first loaded in the container by means of a bucket crane mounted on a lorry placed beside the vehicle assembly. Then, the feeding screw is rotated by means of the power-take off of the tractor so that the pulp is fed into the tube, which is gradually filled and pulled out from the supporting collar. However, this requires the provision of some sort of counterforce equipment behind the tube.
In one such mobile compacting device (see, for instance, U.S. Pat. Nos. 4,949,633 and 4,724,876), the counterforce equipment is in the form of a separate grating or cage which is placed behind the tube before feeding begins and to which are attached two wires. The wires extend in the forward direction and are each wound round a winch drum. The winch drums are mounted one on each side of the trailer and further are provided with some sort of brake device. As the feeding screw operates and the pulp is pressed into the tube, the vehicle assembly is driven forward, which increases the tension in the wires and gives rise to a counterforce effect. Then, more wire is gradually released from the winch drums, and the vehicle assembly is driven forward and the strand laid out. Naturally, the driver of the tractor may also employ the regular brakes of the tractor to achieve a counterforce effect.
However, this prior-art device suffers from a number of drawbacks. The cage and its wires form a bulky and unwieldy structure which, after use, has to be folded and fastened to the trailer. Further, the two wires running on both sides of the laid-out tube may easily tear the plastic tube.
Another disadvantage is that the prior art described above usually requires two operators, one for driving the tractor and one for operating the crane. A further disadvantage is that the feeding screw is connected to the regular power take-off of the tractor, which severely restricts the possibilities of adjusting the degree of compacting, the braking effect and the counterforce effect.
One object of the present invention is, therefore, to obviate these disadvantages by providing a mobile device which is adapted for compacting feedstuff or the like in a tube and in which the need of separate counterforce equipment is much smaller, or does not exist at all, and which further requires a minimum of operators. A further object is that the tube laid on the ground should not be damaged by any wires or other loose equipment.
Another object of the invention is to obviate the above disadvantages by providing a method for compacting feedstuff or the like in a tube to be placed on the ground, without the need of any bulky and unwieldy counterforce equipment.